Mean Correction Research Articles

Usefulness of anterior column release for segmental lordosis restoration in degenerative lumbar kyphosis.

Three-column osteotomies (3COs) for surgical correction of lumbar kyphosis show a strong correction capacity, but this procedure carries high morbidity rates. The anterior column release (ACR) technique was developed as a less invasive procedure. In this study the authors aimed to evaluate sagittal alignment restoration using ACR and to determine factors that affect the degree of correction. This study included 36 patients (68 cases) who underwent ACR of more than one level for adult spinal deformity. Parameters for regional sagittal alignment included segmental lordosis (SL). The parameters for global sagittal alignment included pelvic incidence, lumbar lordosis, sacral slope, pelvic tilt, and sagittal vertical axis (SVA). In addition, the interdiscal height (IDH) and difference of interdiscal angle (DIDA) were measured to evaluate the stiffness of the vertebra segment. The changes in SL were evaluated after ACR and the change of global sagittal alignment was also determined. Factors such as the location of the ACR level, IDH, DIDA, cage height, and additional posterior column osteotomy (PCO) were analyzed for correlation with the degree of SL correction. Thirty-six patients were included in this study. A total of 68 levels were operated with the ACR (8 levels at L2-3, 27 levels at L3-4, and 33 levels at L4-5). ACR was performed for 1 level in 10 patients, 2 levels in 20, and 3 levels in 6 patients (mean 1.9 ± 0.7 levels per patient). Mean follow-up duration was 27.1 ± 4.2 months. The mean SL of the total segment was 0.4° ± 7.2° preoperatively and increased by 15.3° ± 5.5° at the last follow-up (p < 0.001); thus, the mean increase of SL was 14.9° ± 8.1° per one ACR. Global sagittal alignment was also improved following SL restoration with SVA from 101.9 mm to 31.4 mm. The degree of SL correction was correlated with the location of ACR level (p = 0.041) and was not correlated with IDH, DIDA, cage height and additional PCO. This study demonstrated that the mean correction angle of SL was 14.9 per one ACR. The degree of disc space collapse and stiffness of segment did not affect the degree of correction by ACR.

Relationship between Severity of Varus Osteoarthritis of the Knee and Contracture of Medial Structures.

Knees with severe varus osteoarthritis can develop medial structure contracture. However, there is no report on the relationship between severity of varus deformity and contracture of the medial structure. We aimed to determine the threshold angle that could be corrected in proportion to the width of medial osteophyte removal and to examine correction differences between angles larger and smaller than the threshold angle in total knee arthroplasty. This study included 27 varus osteoarthritic knees scheduled for total knee arthroplasty (TKA). A navigation system was used to measure hip-knee-ankle angle (HKA) in all knees at maximum extension and 30˚ and 60˚ flexion, before and after osteophyte removal and with and without external 10 N-m valgus torque loads. Subsequently, resected osteophyte widths were measured. Mean correction angle per 1 mm of osteophyte removal was calculated, and the threshold angle was calculated with the receiver operating characteristic curve. HKA differences were compared against deformities larger and smaller than the threshold angle. Mean osteophyte width was 7.1±2.20 mm. Osteophyte removal produced a mean 3.1° correction, which equaled a 0.4° correction per 1 mm of osteophyte width removal. The varus deformity threshold angle was 9.5°. However, when comparing groups with angles larger and smaller than the threshold angle, there was no significant difference in HKA difference between each step and flexion angle. The threshold angle for expected correction with medial osteophyte removal was 9.5˚. However, because there were no differences in correction between those with angles larger or smaller than this, medial structure contracture seemed to be unrelated to the severity of deformity.

Approximately 80% of Japanese osteoarthritic patients fall out of the safety range in restricted kinematically-aligned total knee arthroplasty in an analysis of preoperative long-leg radiograms

BackgroundRestricted kinematically-aligned total knee arthroplasty (KA-TKA) is a reasonable modification to avoid the alignment outlier that may cause implant failure. However, despite a noted high incidence of constitutional varus in Japanese individuals, there has been no investigation into how many knees require the restriction in restricted KA-TKA (RKA-TKA) among Japanese patients. Therefore, we conducted a study using preoperative long-leg radiograms. MethodsWe studied long-leg radiographs of 228 knees in 114 consecutive patients. The numbers of knees within the safety range and their corrective osteotomy angle in the restriction algorithms advocated by Almaawi et al. (2017) and MacDessi et al. (2020) were evaluated. ResultsAccording to the algorithms used by Almaawi et al. and MacDessi et al., out of 228 knees, 46 (20%) and 39 (17%) fell within the safety range, respectively. The mean correction angles of the hip-knee-ankle angle, lateral distal femoral angle and medial proximal tibial angle were 2.8 ± 3.4°, 0.4 ± 1.4° and 2.4 ± 2.8° in the algorithm used by Almaawi et al., while they were −4.9 ± 4.7°, 1.1 ± 2.5° and −6.0 ± 3.4° in the algorithm used by MacDessi et al. Most of the knees needed to be restricted in order to perform RKA-TKA, regardless of the algorithm used. ConclusionsBased on a preoperative analysis of long-leg radiograms in a Japanese population, most knees fall out of the safety range in RKA-TKA. Surgeons must consider whether to allow component outlier or to perform corrective osteotomy that likely requires soft tissue release.

The implant density does not change the correction rate of the main and the accompanying curves: A comparison between consecutive and intermittent pedicle screw constructs.

The aim of this study was to evaluate the clinical outcomes and the coronal correction rate of the main and accompanying curves of adolescent idiopathic scoliosis (AIS) corrected with pedicle screws inserted consecutively or intermittently. The prospectively collected data of 60 patients (8 men and 52 women; mean age: 14.6±2.5 years) who underwent corrective surgery for AIS between January 2010 and December 2015 were reviewed retrospectively. Two groups were constituted according to the pedicle screw construct type: consecutive pedicle screw construct (CPSC) and intermittent pedicle screw construct (IPSC) groups. The preoperative, early postoperative, and 24-month follow-up radiographs and the Scoliosis Research Society-22 (SRS-22) scores were reevaluated. The Cobb angle of the main and accompanying curves, the correction rate, and the flexibility of the curves were calculated. The mean preoperative Cobb angles were 57.03° and 57.46°, the mean postoperative Cobb angles were 14.93° and 14.4°, and the mean correction rates were 76.22% and 75.31% in IPSC and CPSC groups, respectively (p>0.05). The preoperative and postoperative accompanying curve magnitudes and correction rates were similar (p>0.05). These radiographic outcomes were also consistent with the SRS-22 scores. Both the pedicle screw constructs had satisfactory outcomes following the surgery, which were confirmed by both the SRS-22 scores and radiographs taken perioperatively and at follow-ups. The IPSC and CPSC groups did not demonstrate a significant change in the correction rate of the main and minor or major accompanying structural and nonstructural curves, and also in the SRS-22 scores. Level III, Retrospective comparative study.

Scoliosis flexibility correlates with post-operative outcomes following growth friendly surgery.

The purpose of this study was to determine the relationship between pre-operative scoliosis flexibility and post-operative outcomes, including curve correction and complications, for patients who have been treated with growth friendly surgery (GFS) for early onset scoliosis (EOS). The study was conducted as a retrospective review of prospectively collected data from an international, multicenter, EOS database. EOS patients with pre-operative flexibility radiographs (traction or bending) were identified. Pre-operative flexibility and immediate post-operative correction were calculated for each patient. Post-operative complications were recorded at final follow-up. Pearson correlations were determined for flexibility vs correction for all patients and were compared between etiologies and between device types (MCGR, TGR, VEPTR). 107 patients (14 congenital, 43 neuromuscular, 31 syndromic, 19 idiopathic) with mean age 7.1years at index surgery were identified. Mean pre-operative scoliosis was 77°. Mean flexibility of 36% was not significantly different between etiologies. Mean immediate post-operative scoliosis was 46° (p < 0.001 vs. pre-operative) with mean correction of 38%. Correction rate was not significantly different between etiologies; however, correction rate was different between device types (MCGR 45%, TGR 40%, VEPTR 14%; p = < 0.001). Pearson correlation for flexibility vs correction was fair (r = 0.37, p < 0.001). This correlation was observed for idiopathic (r = 0.53, p = 0.020) and neuromuscular (r = 0.46, p = 0.0020) scoliosis, but not for congenital or syndromic scoliosis. At a mean of 6.1year follow-up (minimum 2years to 15.5years), 60 of 81patients (74%) experienced at least one complication. Odds ratio for developing a complication was 3.00 (1.03-8.76) for patients with pre-operative flexibility < 45% (p < 0.05). As lower pre-operative flexibility was associated with less scoliosis correction and with a higher risk of post-operative complications, curve flexibility should be considered when deciding upon the timing of growth friendly surgery. Level III-retrospective comparative study.

Radiological Evaluation of Combined Anteroposterior Fusion with Vertebral Body Replacement Using a Minimally Invasive Lateral Approach for Osteoporotic Vertebral Fractures: Verification of Optimal Surgical Procedure.

The combined anteroposterior fusion with vertebral body replacement (VBR) using a wide footplate expandable cage with a minimally invasive lateral approach has been widely used for pseudoarthrosis after osteoporotic vertebral fractures. The purpose of this study is to evaluate the radiological results of combined anteroposterior surgery using VBR and to recommend the optimal procedure. Thirty-eight elderly patients were included in this study. The mean preoperative local kyphosis angle was 29.3°, and the mean correction loss angle was 6.3°. Cage subsidence was observed in ten patients (26.3%), and UIV or LIV fracture in twelve patients (31.6%). Patients with cage subsidence were compared to those without cage subsidence to determine the causal factors. The mean number of fixed vertebrae was 5.4 vertebrae with cage subsidence and 7.4 vertebrae without cage subsidence. In addition, to precisely clarify the optimal number of fixed vertebrae, those patients with two above–two below fixation were compared to those with less than two above–two below fixation, which revealed that the correction loss angle was significantly less in two above–two below fixation (p = 0.016). Based on these results, we recommend at least two above–two below fixation with VBR to minimize the correction loss angle and prevent cage subsidence.

A 540° posterior-anterior-posterior approach for 360° fused rigid severe cervical kyphosis: patient series

BACKGROUNDTreatment of severe rigid 360° fused cervical kyphosis (CK) is challenging and often requires a combined approach for ankylosis release, establishment of sagittal balance, and fixation with fusion.OBSERVATIONSFour patients with iatrogenic 360° fused severe rigid CK (Cobb angle ≥40°) were enrolled for this retrospective analysis. All patients in the case series were female, with an average age of 27 years. All patients previously underwent posterior laminectomy/laminoplasty and cervical tumor resection when they were children (13–17 years). They underwent correction surgery with a 540° posterior-anterior-posterior approach. Preoperative and final follow-up radiography and computed tomography (CT) were used to evaluate kyphosis correction, internal fixation implants, and bone fusion. The preoperative and final follow-up average C2–7 Cobb angles were −32.4° ± 12.0° and 5.3° ± 7.1°, respectively. Preoperative and final follow-up CK angles averaged −47.2° ± 7.4° and −0.9° ± 16.1°, respectively. The mean correction angle was 46.3° ± 9.6°. At final follow-up, CT showed stable fixation and solid bone fusion.LESSONSThe rare iatrogenic severe kyphosis with 360° ankylosis requires a combined approach. The 540° posterior-anterior-posterior approach can completely release the bony fusion, and the CK can be corrected using an anterior plate. This technique can achieve good results and is an effective strategy.

Makoplasty medial unicondylar knee replacement: Correction or postoperative angle matters?

Various considerations prevail around optimal postoperative varus deformity, correction angle and physiological constitutional varus deformity. The goal of our present study was to understand correlation between these parameters and their influence over Western Ontario McMaster University Osteoarthritis Index scale (WOMAC). Consecutive robotic-arm-assisted medial onlay fixed bearing unicompartmental knee arthroplasty (UKA) in 143 knees studied. WOMAC score was recorded preoperatively and at specific intervals after surgery for consecutive 2 years. Mean preoperative and postoperative varus deformities were 10.2° and 4.8°, respectively, and mean correction angle was 5.4°. The preoperative varus and correction angles were found well correlated (r=0.815). The amount of improvement in the WOMAC total score was not influenced by the postoperative varus angle. The correction angle has a stronger correlation with preoperative varus deformity, and postoperative varus deformity does not imply favourable clinical outcomes.

The Pantheon+ analysis: Improving the redshifts and peculiar velocities of Type Ia supernovae used in cosmological analyses

AbstractWe examine the redshifts of a comprehensive set of published Type Ia supernovae, and provide a combined, improved catalogue with updated redshifts. We improve on the original catalogues by using the most up-to-date heliocentric redshift data available; ensuring all redshifts have uncertainty estimates; using the exact formulae to convert heliocentric redshifts into the Cosmic Microwave Background (CMB) frame; and utilising an improved peculiar velocity model that calculates local motions in redshift-space and more realistically accounts for the external bulk flow at high-redshifts. We review 2607 supernova redshifts; 2285 are from unique supernovae and 322 are from repeat-observations of the same supernova. In total, we updated 990 unique heliocentric redshifts, and found 5 cases of missing or incorrect heliocentric corrections, 44 incorrect or missing supernova coordinates, 230 missing heliocentric or CMB frame redshifts, and 1200 missing redshift uncertainties. The absolute corrections range between$10^{-8} \leq \Delta z \leq 0.038$, and RMS$(\Delta z) \sim 3{\times 10^{-3}}$. The sign of the correction was essentially random, so the mean and median corrections are small:$4{\times 10^{-4}}$and$4{\times 10^{-6}}$respectively. We examine the impact of these improvements for$H_0$and the dark energy equation of statewand find that the cosmological results change by$\Delta H_0 = -0.12\,\mathrm{km\,s}^{-1}\mathrm{Mpc}^{-1}$and$\Delta w = 0.003$, both significantly smaller than previously reported uncertainties for$H_0$of 1.0$\mathrm{km\,s}^{-1}\mathrm{Mpc}^{-1}$andwof 0.04 respectively.

ЗАСТОСУВАННЯ ПОЛІНОМІАЛЬНИХ ПОПРАВОК ДЛЯ ПОБУДОВИ ОПТИМАЛЬНОЇ ОДНОВИМІРНОЇ МОДЕЛІ ГУСТИНИ МАНТІ

In this work, an optimal one-dimensional density model was obtained, corresponding to the velocity curve for one of the mantle domain under the Ukrainian shield. When obtaining a one-dimensional density model, only the Earth's mass and seismic velocities are known physical parameters. The density is obtained by solving the Adams-Williamson equation, the use of which is possible under the assumption that the density is created only by the weight of the upper layers, with a homogeneous composition of the mantle. Some approximation to the real density distribution gives a seismic parameter that scales the obtained densities in accordance with the geometry of the seismic velocity distribution, while, as shown by our studies, the obtained density values are not absolute, but only an approximation corresponding to the equation is used. In order to obtain a density distribution we transform the first approximation obtained from the Adams-Williamson equation. This paper shows several options for transformation; based on the arithmetic mean correction for 5 reference mantle models (PEMC, PEMA, PREM, AK135, IASP91); using control points representing seismic boundaries to determine the intervals for computation of density using the Adams-Williamson equation; when introducing corrections in the form of the difference between the polynomials for the theoretical density curve and that obtained by the Adams-Wilmson equation for the IASP91 model. The density curve obtained by the last method is not distorted by the introduced density jumps from the IASP91 model, correspond to positions of seismic boundaries along the inflections of the P-velocity curve. The density curve obtained from the Adams-Williamson equation is transformed into a curve that is as close as possible to the geometry of the inherent curve seismic velocity of P and S waves. In our opinion, the density curve obtained using the difference polynomial shows the most approximate solution to the optimal density model for a given seismic velocity distribution, in our case, for the mantle domain under the Ukrainian shield with center coordinates 28.25Å 49N.

Effect of Limb Alignment in Medial Unicompartmental Knee Arthroplasty on Functional Outcomes and Patient Satisfaction

Background: Unicompartmental knee arthroplasty (UKA) is effective in the treatment of symptomatic unicompartmental knee osteoarthritis. However, ideal limb alignment and acceptable changes of alignment remains contentious. Purpose: The purpose of this study is to look at the impact of post-operative mechanical limb alignment on short term functional outcomes in an Asian population. Methods: We performed a retrospective review of all mobile bearing, Oxford UKAs performed from July 2016 to January 2019 by a single-surgeon (43 patients, 47 knees). Pre- and post-operative weight bearing radiographic parameters were measured, as well as functional assessments via Oxford knee society (OKS) scores and the original Knee society score (KSS). Results: The post-operative mechanical axis mean was varus 4.3° (range valgus 2° to varus 10°), with a mean correction of 4.4° towards valgus. All our patients had an improvement in functional scores and range of movement post-operatively, however, patients with pre-operative alignment of varus 15° did not meet the cut off for minimal important change (MIC) in OKS scores. More varus pre-operative alignment resulted in a larger degree of change in limb alignment post-operatively. A larger change in alignment was also associated with higher satisfaction scores in patients. Conclusion: Post-operative limb alignment of up to 10° varus does not compromise short term functional outcome scores in medial UKA. Caution is advised when selecting patients with varus 15° and above for UKA as they may not be able to achieve a minimal important change in functional scores post-operatively.

Does a “Spot Weld” with a 1st to 2nd Metatarsal Base Screw Maintain Correction of the Modified Lapidus Procedure? A Retrospective Radiographic Review

Category:Bunion; Midfoot/ForefootIntroduction/Purpose:The Lapidus 1st tarsometatarsal (TMT) arthrodesis has gained popularity for its ability to correct large deformities especially in cases of medial column instability. Even with solid fusion, instability between the 1st and 2nd columns can result in loss of intermetatarsal (IM) angle correction over time. Anecdotally, a 'spot weld' between the lateral 1stmetatarsal and medial 2nd metatarsal bases seems to predict long term maintenance of IM correction. The purpose of the study is to review cases of Lapidus 1st TMT arthrodesis with supplemental screw fixation from the 1stto 2nd metatarsal base for maintenance of IM correction and determine whether a 'spot weld' is predictive of maintenance and identify an optimum position of the 1st to 2nd metatarsal screw to achieve the 'spot weld.Methods:A retrospective radiographic review of cases by a single surgeon over the past five years was performed. All cases of tarsometatarsal fusion were queried and reviewed. Inclusion criteria included primary arthrodesis of the 1st TMT joint with supplemental fixation between the 1st and 2nd metatarsal bases, availability of appropriate radiographic image and at least 4 months follow up. Exclusion criteria included 1st TMT fusion without 1st-2nd metatarsal screw fixation, multiple TMT or midfoot fusion, Charcot neuroarthropathy, and revision fusion. A standard surgical technique was utilized with an in situ joint debridement, specific preparation to the medial 2ndmetatarsal base and adjacent lateral 1st metatarsal base, autogenous bone grafting and hardware construct at the 1stTMT joint consisting of compression screw from the 1st metatarsal to the 2nd cuneiform, screw fixation from 1st to 2ndmetatarsal bases and either locking plate or compression staple fixation dorsally across the 1st TMT joint.Results:90 cases (77 patients) met the inclusion criteria with average follow up of 309 days. Fusion of the 1st TMT occurred in 87/90 (96.7%) cases with 76 dorsal plate, 10 with dorsal staple and 4 with all screws. There was no incidence of complications related to the 1-2 screw. The mean pre-operative IM 1-2 angle was 14.90 degrees, with mean correction to 6.22 degrees post operative and final maintained correction at 7.10 degrees with mean loss of 0.87 degrees. There were 'spot welds' in 65/90 (72.2%) with a mean loss of correction of 0.48 degree versus loss of 1.88 degrees in the 'no spot weld' subgroup (p<0.001). Cases with no spot weld and screw lucency lost 2.25 degrees (p<0.001).Conclusion:Loss of IM 1-2 correction can occur due to instability between the 1st and 2nd columns even in cases of solid 1st TMT arthrodesis. The achievement of a 'spot weld' via careful preparation, bone grafting and use of a 1st to 2nd metatarsal base screw as part of a Lapidus construct was found to maintain correction with minimal loss (0.87 degree) versus cases where no 'spot weld' was achieved. Cases with no 'spot weld' that developed screw lucency had the greatest loss of correction. No statistical difference in screw position between groups was found.

Impact of Covid-19 Pandemic on Students Learning Outcomes in Universities in Osun State, Nigeria

The study investigated the impact of COVID-19 pandemic in the process of education of students from Osun Universities in Nigeria. The study is a descriptive one; a sample of 360 students from the universities in Osun State formed the participants for the study. The instrument for data collection was a questionnaire structured by the researcher for data collection and its reliability level was 0.83. Data collected were analysed, using descriptive statistics, specifically mean, standard deviation, frequency counts and Person Product Moment Correction (PPMC). The findings of the study revealed that COVID-19 pandemic has negative effect on students’ learning outcomes from Osun State in Nigeria. The study revealed that there is no significant difference in the learning outcomes of students, depending on the type of school. Finally, the findings revealed that gender does not significantly differentiate the learning outcomes of the respondent students in Osun, Nigeria, under the COVID-19 pandemic situation. The following recommendations were made: government should consider the need to build good schools and equip them with modern digital facilities; government should ensure inclusion of online teaching such as integrated digital learning platforms, video lessons, broadcasting through radio and TV etc. to supplement the normal classroom teaching; educators as well as students must be trained on how to handle and use online educational devices; educators must spend quality time to prepare and make their lessons creative, interactive, relevant, student-centred and group-based; parents should pay personal attention to monitor and supervise their children until they adapt to online teaching environment; and government aid is needed in terms of investing in educational tools of the future alongside a total revamp of the educational sector as well as reforms in the national curriculum post-pandemic.

Acoustic correction factor estimate for compensating vertical diel migration of small pelagics

Differences in acoustic estimates of small pelagic fish biomass, due to data acquisition during daytime and nighttime surveys, have been recognized for many years as a problem in acoustic surveys. In the absence of a single rule for all species and for all locations, some expert groups identified specific time intervals for acoustic data acquisition in relation to the schooling behavior of the target species. In the Mediterranean Sea, the research groups working in the MEDIAS (Mediterranean International Acoustic Survey) agreed on the importance that acoustic sampling are conducted only during day-time. Only when available time does not permit to complete the survey during daytime, data collection might be extended. In this case, working on data collected during both daytime and nighttime, a bias may occur in the biomass estimates. In order to evaluate and correct such bias, specific experiments were performed in some geographical sub-areas of the Mediterranean Sea. The data analysis allowed the estimation of a mean correction factor for the Strait of Sicily, where five surveys were carried out in different years. The correction factor was estimated also for the Adriatic Sea, Tyrrhenian Sea and Northern Spain; the observed variability among areas highlighted the importance of the spatial and temporal coverage of the survey area in order to obtain reliable estimates of the correction factor. Further studies are necessary to improve the interpretation of the obtained estimates in relation to area-related peculiarities such as zooplankton composition and abundance along with small pelagic fish community structure.

Partial Pedicle Subtraction Osteotomy for Patients with Thoracolumbar Fractures : Comparative Study between Burst Fracture and Posttraumatic Kyphosis.

ObjectiveTo evaluate the surgical outcomes of partial pedicle subtraction osteotomy (PPSO) in patients with thoracolumbar fractures and compare the outcomes of PPSO for burst fractures with those for posttraumatic kyphosis (PTK). MethodsFrom June 2013 to May 2019, 20 consecutive adult patients underwent PPSO for thoracolumbar fractures at the levels of T10 to L2. Of these patients, 10 underwent surgery for acute fractures (burst fractures), and 10 for sequelae of thoracolumbar fractures (PTK). Outcomes of PPSO were evaluated and compared between the groups. ResultsTwenty patients (each 10 patients of burst fractures and PTK) with a mean age of 64.7±11.1 years were included. The mean follow-up period was 21.8±11.0 months. The mean correction of the thoracolumbar angle was -34.9°±18.1° (from 37.8°±20.5°preoperatively to 2.8°±15.2° postoperatively). The mean angular correction at the PPSO site was -38.4°±13.6° (from 35.5°±13.6° preoperatively to -2.9°±14.1° postoperatively). The mean preoperative sagittal vertical axis was 93.5±6.7 cm, which was improved to 37.6±35.0 cm postoperatively. The mean preoperative kyphotic angle at the PPSO site was significant greater in patients with PTK (44.8°±7.2°) than in patients with burst fractures (26.2°±12.2°, p=0.00). However, the mean postoperative PPSO angle did not differ between the two groups (-5.9°±15.7° in patients with burst fractures and 0.2°±12.4° in those with PTK, p=0.28). The mean angular correction at the PPSO site was significantly greater in patients with PTK (-44.6°±10.7°) than in those with burst fractures (-32.1°±13.7°, p=0.04). The mean operation time was 188.1±37.6 minutes, and the mean amount of surgical bleeding was 1030.0±533.2 mL. There were seven cases of perioperative complications occurred in five patients (25%), including one case (5%) of neurological deficit. The operation time, surgical bleeding, and complication rates did not differ between groups. ConclusionIn cases of burst fracture, PPSO provided enough spinal cord decompression without corpectomy and produced sagittal correction superior to that achieved with corpectomy. In case of PTK, PPSO achieved satisfactory curve correction comparable to that achieved with conventional PSO, with less surgical time, less blood loss, and lower complication rates. PPSO could be a viable surgical option for both burst fractures and PTK.

Isthmic spondylolisthesis treated with circumferential arthrodesis (ALIF and posterior fixation): correction, fusion and indirect decompression

There is no consensus regarding the choice of the surgical technique for isthmic spondylolisthesis treatment, although they all aim to a common goal, achieving fusion at the index level while restoring an appropriate lordosis and remove potential radicular compression. Analyze outcome of circumferential arthrodesis (CA) with ALIF (Anterior Lumbar Interbody Fusion) and pedicle screw fixation for the treatment of all-grade isthmic spondylolisthesis, with indirect neurological decompression. Retrospective study of isthmic spondylolisthesis treated with CA, with one-year follow-up. Clinical scores were collected at one year: VAS-L, VAS-R and ODI. Pelvic parameters, L4-S1 lordosis and at index and adjacent levels, and lumbo-sacral angle (LSA) were measured pre- and post-operatively and at last follow-up. Foraminal surface and diameters were measured pre- operatively and at follow-up on CT-Scan. Level of evidence: IV. 87 patients were included. Mean VAS-L was 2.3, mean VAS-R was 1, and mean ODI was 13.8%. 10% of the patients presented a high-grade spondylolisthesis and 50% a grade II. Mean lordosis at index level shifted from 6° to 18°, L4-S1 lordosis increased from 37 to 45° and LSA shifted from 116 to 125° (p<0.001). The foraminal surface increased from 50mm 2 to 70mm 2 at last follow-up mostly through the supero-inferior diameter, shifting from 7.4mm to 9.5mm (p<0.001). In LSA<90° group, mean correction was 20° at index level, 13° at L4-S1 and 21° for LSA versus 11°, 8° and 8° respectively in LSA>90° group (p<0.001). Fusion rate was estimated at 96.5%. One infection, 5 sympathetic dysfunctions, one retrograde ejaculation, one iliac vein injury, one incisional hernia, one lateral femoral cutaneous nerve injury and two adjacent syndromes have been noted. CA is an efficient technique for the treatment of isthmic spondylolisthesis of all grades, with an acceptable rate of complications. It allows a restoration of the regional lordosis as well as a foraminal widening, avoiding additional decompression.

Effect of stress ratios on corrosion fatigue life of high‐strength steel wires

AbstractIn order to discuss the influence of the stress ratio on the corrosion fatigue life of high‐strength steel wires, a theoretical and experimental investigation was conducted on corroded steel wires at three different stress ratios (R = 0.1, 0.3, and 0.5) under axial tensile fatigue loading. Different S‐N curves of corroded steel wires were regressed from test data. The stress method based on eight mean stress correction models, the strain energy method, and the facture mechanics method considering environmental corrosion and crack closure were proposed to estimate the fatigue life. Preliminary results show that corrosion can reduce the ultimate strength, the yield strength, and the fatigue life. There is a negative correlation between corrosion fatigue life and stress ratio. When R &gt; 0, fatigue life predicted results by using the Morrow and Marin models in the stress method are more efficient and accurate than other models. Likewise, the Zheng model in the fracture mechanics method is in better agreement with test results. The error and scatter of the strain energy method are relatively large. Therefore, the Morrow, Marin, and Zheng models are more suitable to predict the corrosion fatigue life of high‐strength steel wires under different stress ratios.

Short-Term Outcomes of Robotic Lateral Unicompartmental Knee Arthroplasty: An Indian Perspective.

Lateral UKA is a technically more challenging procedure than medial UKA accounting for < 1% of all knee arthroplasties. Robotic UKA for lateral compartment arthritis is rare and has not been reported in India. This is a prospective single-centre clinical study of six patients (five females and one male) who underwent robotic-arm-assisted lateral UKA (RALUKA) between May 2018 and January 2020 with patient-specific 3D-CT preoperative plan. Overall satisfaction on a five-level Likert scale, clinical outcome based on the KOOS and MFJS and radiological outcomes based on the HKA axis, femorotibial angle (FTA), tibial posterior slope (PS) obtained were compared preoperatively and postoperatively. At a mean follow-up period of 23.84months, among six patients 33.3% very satisfied, 50% satisfied and 16.7% felt neutral. The mean KOOS changed from 63.03 ± 3.52 to 93.95 ± 3.25 and the mean MFJS was 75.41 ± 10.29 postoperatively. The mean HKA axis changed from 175.81° ± 2.88 valgus to 179.99° ± 2.14 neutral alignment. The mean correction attained was from 4.19° ± 2.88 valgus deformity to 0.01° ± 2.14. The mean FTA and the mean PS changed from 7.34° ± 4.14 of valgus to 1.92° ± 1.85 of valgus and 83.44° ± 1.77 to 85.38° ± 2.10, respectively. The mean preoperative and postoperative KOOS showed a statistical significance with a p value of < 0.001 (< 0.05), showing significant improvement with RALUKA. RALUKA is a promising surgical option for lateral compartment OA of the knee.

Is single posterior approach sufficient for effective hemivertebra resection and correction of nonflexible curves? A prospective study

Background: The purpose of this study was to evaluate the results of posterior-only resection of hemivertebrae in correction of congenital spinal deformities. Methods: Thirty consecutive patients with scoliosis, kyphosis, or kyphoscoliosis that was caused by congenital hemivertebra were included. Preoperative calculations of the curve degree and stiffness were obtained, and postoperative magnitude of corrections were calculated. The mean percentage of correction was measured. Intraoperative and postoperative complications were stated. The mean follow-up period was 48 mo. Results: The mean age of the patients was 11 yr. Scoliosis was found in 20 patients, pure kyphosis was found in six patients, and kyphoscoliosis was found in four patients. The deformity was in the thoracic region in nine patients, thoracolumbar region in 16, and lumbar region in five. Each patient had a single hemivertebra and primary posterior hemivertebra resection. The mean preoperative coronal Cobb angle in both the scoliosis and kyphoscoliosis patients was 49 degrees. The angle improved to a mean of 10.8 degrees at final follow-up with mean correction of 38.2 degrees. The mean preoperative local kyphosis angle in the kyphosis and kyphoscoliosis patients was 73.1 degrees. This improved to a mean of 21.1 degrees postoperatively with mean correction of 52 degrees. The mean preoperative regional angulation in those patients was 67.1 degrees, which improved to a mean of 24.6 degrees postoperatively with a mean correction of 42.6 degrees. Improvements in all these values were statistically highly significant (P &lt; 0.001). Complications were recorded in six patients and included dural tear, pleural tear, and postoperative wound infection, which were managed. Conclusions: The posterior-only approach in hemivertebra resection can achieve good deformity correction and solid fusion with low risk of neurological complications. Level of Evidence: Level IV.

Standardizing SPECT/CT dosimetry following radioembolization with yttrium-90 microspheres

BackgroundMultiple post-treatment dosimetry methods are currently under investigation for Yttrium-90 (^{90}hbox {Y}) radioembolization. Within each methodology, a variety of dosimetric inputs exists that affect the final dose estimates. Understanding their effects is essential to facilitating proper dose analysis and crucial in the eventual standardization of radioembolization dosimetry. The purpose of this study is to investigate the dose differences due to different self-calibrations and mass density assignments in the non-compartmental and local deposition methods. A practical mean correction method was introduced that permits dosimetry in images where the quality is compromised by patient motion and partial volume effects.MethodsTwenty-one patients underwent ^{90}hbox {Y} radioembolization and were imaged with SPECT/CT. Five different self-calibrations (FOV, Body, OAR, Liverlung, and Liver) were implemented and dosimetrically compared. The non-compartmental and local deposition method were used to perform dosimetry based on either nominal- or CT calibration-based mass densities. A mean correction method was derived assuming homogeneous densities. Cumulative dose volume histograms, linear regressions, boxplots, and Bland Altman plots were utilized for analysis.ResultsUp to 270% weighted dose difference was found between self-calibrations with mean dose differences up to 50 Gy in the liver and 23 Gy in the lungs. Between the local deposition and non-compartmental methods, the liver and lung had dose differences within 0.71 Gy and 20 Gy, respectively. The local deposition method’s nominal and CT calibration-based mass density implementations dosimetric metrics were within 1.4% in the liver and 24% in the lungs. The mean lung doses calculated with the CT method were shown to be inflated. The mean correction method demonstrated that the corrected mean doses were greater by up to sim 5 Gy in the liver and lower by up to sim 12 Gy in the lungs.ConclusionsThe OAR calibration may be utilized as a potentially more accurate and precise self-calibration. The non-compartmental method was found more comparable to the local deposition method in organs that were more homogeneous in mass densities. Due to the potential for inflated lung mean doses, the non-compartmental and local deposition method implemented with nominal mass densities is recommended for more consistent dosimetric results. If patient motion and partial volume effects are present in the liver, our practical correction method will calculate more representative doses in images suboptimal for dosimetry.